Anazawa Onsen

Anazawa Onsen in Nagano Prefecture flows with sulfate-rich thermal waters in a prefectural landscape of exceptional geothermal richness, where the volcanic geology of the Japanese Alps and the active volcanic systems of the Fossa Magna zone produce sulfate springs of considerable mineral quality across multiple mountain districts and highland valleys. The spring's sulfate mineral composition reflects the volcanic sulfate chemistry of the region and, within a long thermal tradition, has long made Anazawa Onsen a welcome place of relaxation for mountain hikers and outdoor enthusiasts who engage with Nagano's demanding alpine terrain. The name Anazawa, suggesting a spring in a hollow or cave-like valley — ana meaning a hole or cave, sawa meaning a marshy stream or valley — evokes a secluded, enclosed setting where the thermal spring emerges from the sheltered geological feature that gives it its identity, connecting the experience of bathing in its sulfate waters to the intimate, cave-sheltered character of its natural source environment.